Oops, it doesn't look like 'nernernynerner day' is a national day..

Other days

kale

Kale Day
ride the wind

Ride The Wind Day
bounce

Bounce Day
coffee

Coffee Day
pick me

Pick Me Day
polyamory

Polyamory Day
one

One Day
cuddle up

Cuddle Up Day
mean girls

Mean Girls Day
gallery

Gallery Day